use std::fs;
use std::io;
use std::path::{Path, PathBuf};

pub fn backup_path(path: &Path) -> PathBuf {
    sibling_with_suffix(path, "bak")
}

pub fn corrupt_path(path: &Path) -> PathBuf {
    sibling_with_suffix(
        path,
        &format!("corrupt.{}", uuid::Uuid::new_v4().hyphenated()),
    )
}

pub fn temp_path(path: &Path) -> PathBuf {
    sibling_with_suffix(path, &format!("tmp.{}", uuid::Uuid::new_v4().hyphenated()))
}

pub fn write_with_backup(path: &Path, contents: &[u8]) -> io::Result<()> {
    if let Some(parent) = path.parent() {
        fs::create_dir_all(parent)?;
    }

    let temp_path = temp_path(path);
    fs::write(&temp_path, contents)?;

    let backup_path = backup_path(path);
    if path.exists() {
        fs::copy(path, &backup_path)?;
        fs::remove_file(path)?;
    }

    match fs::rename(&temp_path, path) {
        Ok(()) => Ok(()),
        Err(error) => {
            let _ = fs::remove_file(&temp_path);
            if !path.exists() && backup_path.exists() {
                let _ = fs::copy(&backup_path, path);
            }
            Err(error)
        }
    }
}

fn sibling_with_suffix(path: &Path, suffix: &str) -> PathBuf {
    let file_name = path
        .file_name()
        .and_then(|value| value.to_str())
        .unwrap_or("proxywarden-file");

    path.with_file_name(format!("{file_name}.{suffix}"))
}